Unexpected number of closed streams

In this piece of (simplified) code below I get as a unexpected result : "4 streams flushed" after opening 1 file and flushing all open streams with _flushall afterwards.I cannot figure out which 3 other streams were opened.

Comments

: In this piece of (simplified) code below I get as a unexpected result : "4 streams flushed" after opening 1 file and flushing all open streams with _flushall afterwards.: I cannot figure out which 3 other streams were opened.